Method of scrambling reference signals, device and user equipment using the method
A Method of scrambling reference signals, device and user equipment using the method are provided. In the method, a plurality of layers of reference signals assigned on predetermined radio resource of a plurality of layers of resource blocks with the same time and frequency resources are scrambled, the method comprising: an orthogonalizing step of multiplying each layer of reference signal selectively by one of a plurality of orthogonal cover codes (OCCs) with the same length wherein the OCC multiplied to a first layer of reference signal can be configured as different from those multiplied to other layers of reference signals; and a scrambling step of multiplying all of symbols obtained from the OCC multiplied to each of the other layers of reference signals by a symbol-common scrambling sequence wherein the symbol-common scrambling sequences can be different from each other for reference signals multiplied by the same OCC.
1. A method of scrambling a plurality of layers of reference signals assigned on predetermined radio resources of a plurality of layers of resource blocks with the same time and frequency resources, comprising:
an orthogonalizing step of multiplying each layer of reference signal selectively by one of a plurality of orthogonal cover codes (OCCs) with the same length, wherein the OCC multiplied to a first layer of reference signal can be configured as different from those multiplied to other layers of reference signals; and
a scrambling step of multiplying all of symbols obtained from the OCC multiplied to each of the other layers of reference signals by a symbol-common scrambling sequence, wherein the symbol-common scrambling sequences can be different from each other for reference signals multiplied by the same OCC,
wherein the symbol-common scrambling sequence is expressed as r′ l,n s (m) which is defined by
r
l
,
n
s
′
(
m
)
=
1
2
(
1
-
2
·
c
(
2
m
)
)
+
j
1
2
(
1
-
2
·
c
(
2
m
+
1
)
)
,
m
=
0
,
1
,
…
,
N
RB
max
,
DL
-
1
where n s is the slot number within a radio frame and l is the OFDM symbol number within the slot, the pseudo-random sequence c(i) is defined in Section 7.2 of 3GPP TS 36.211 V10.4.0, and its pseudo-random sequence generator is initialized with c init =2 10 ·(7·(n s +1)+l+1)·(2·N ID IMRS +1)+2·N ID IMRS +N CP at the start of each OFDM symbol where N ID IRMS indicates IM-RS ID and
N
CP
=
{
1
for
normal
CP
0
for
extended
CP
.
2. A method of scrambling a plurality of layers of reference signals assigned on predetermined radio resources of a plurality of layers of resource blocks with the same time and frequency resources, comprising:
an orthogonalizing step of multiplying each layer of reference signal selectively by one of a plurality of orthogonal cover codes (OCCs) with the same length, wherein the OCC multiplied to a first layer of reference signal can be configured as different from those multiplied to other layers of reference signals; and
a scrambling step of multiplying all of symbols obtained from the OCC multiplied to each of the other layers of reference signals by a symbol-common scrambling sequence, wherein the symbol-common scrambling sequences can be different from each other for reference signals multiplied by the same OCC,
wherein the symbol-common scrambling sequence which is expressed as r′ l′,n s (m) is mapped to complex-valued modulation symbols a k,l (p) used as reference symbols on antenna port p according to
a
k
,
l
(
p
)
=
w
l
″
·
r
l
′
,
n
s
′
(
m
′
)
,
where
k
=
k
′
+
12
m
+
{
-
0
for
p
∈
{
15
,
16
}
,
normal
cyclic
prefix
-
6
for
p
∈
{
17
,
18
}
,
normal
cyclic
prefix
-
1
for
p
∈
{
19
,
20
}
,
normal
cyclic
prefix
-
7
for
p
∈
{
21
,
22
}
,
normal
cyclic
prefix
-
0
for
p
∈
{
15
,
16
}
,
extended
cyclic
prefix
-
3
for
p
∈
{
17
,
18
}
,
extended
cyclic
prefix
-
6
for
p
∈
{
19
,
20
}
,
extended
cyclic
prefix
-
9
for
p
∈
{
21
,
22
}
,
extended
cyclic
prefix
l
=
l
′
+
{
l
″
CSI
reference
signal
configurations
0
-
19
,
normal
cyclic
prefix
2
l
″
CSI
reference
signal
configurations
20
-
31
,
normal
cyclic
prefix
l
″
CSI
reference
signal
configurations
0
-
27
,
extended
cyclic
prefix
w
l
″
=
{
1
if
mod
(
N
ID
IMRS
,
2
)
=
0
(
-
1
)
l
″
if
mod
(
N
ID
IMRS
,
2
)
=
1
l
″
=
0
,
1
m
=
0
,
1
,
…
,
N
RB
DL
-
1
m
′
=
m
+
⌊
N
RB
max
,
DL
-
N
RB
DL
2
⌋
and the quantity (k′,l′) and the necessary conditions on n s are given by Tables 6.10.5.2-1 and 6.10.5.2-2 in 3GPP TS 36.211 V10.4.0 for normal and extended cyclic prefix respectively.
3. A method of scrambling a plurality of layers of reference signals assigned on predetermined radio resources of plurality of layers of resource blocks with the same time and frequency resources, comprising:
an orthogonalizing step of multiplying each layer of reference signal selectively by one of a plurality of orthogonal cover codes (OCCs) with the same length, wherein the OCC multiplied to a first layer of reference signal can be configured as different from those multiplied to other layers of reference signals;
a scrambling step of multiplying all of symbols obtained from the OCC multiplied to each of the other layers of reference signals by a symbol-common scrambling sequence, wherein the symbol-common scrambling sequences can be different from each other for reference signals multiplied by the same OCC;
a second scrambling step of multiplying all of symbols obtained from the OCC multiplied to each layer of reference signal respectively by different symbol-specific scrambling sequences which can be configured as common to all of the plurality of layers of reference signals; and
a third scrambling step of multiplying all of symbols obtained from the OCC multiplied to the first layer of reference signal by another symbol-common scrambling sequence which is the same as one of or different from all of the symbol-common scrambling sequences multiplied to the other layers of reference signals.
4. A device of scrambling a plurality of layers of reference signals assigned on predetermined radio resources of a plurality of layers of resource blocks with the same fine and frequency resources, comprising:
an orthogonalizing unit which, in operation, multiplies each layer of reference signal selectively by one of a plurality of orthogonal cover codes (OCCs) with the same length, wherein the OCC multiplied to a first layer of reference signal can be configured as different from those multiplied to other layers of reference signals;
a scrambling unit which, in operation, multiplies all of symbols obtained from the OCC multiplied to each of the other layers of reference signals by a symbol-common scrambling sequence, wherein the symbol-common scrambling sequences can be different from each other for reference signals multiplied by the same OCC;
a second scrambling unit which, in operation, multiplies all of symbols obtained from the OCC multiplied to each layer of reference signal respectively by different symbol-specific scrambling sequences which can be configured as common to all of the plurality of layers of reference signals; and
a third scrambling unit which, in operation, multiplies all of symbols obtained from the OCC multiplied to the first layer of reference signal by another symbol-common scrambling sequence which is the same as one of or different from all of the symbol-common scrambling sequences multiplied to the other layers of reference signals.